The cost of the proposed circuit was compared with that of a
PFC buck converter and a multiple-string LED driver. The
proposed circuit requires one bidirectional switch, the PFC
buck converter requires one unidirectional switch, but the
multiple-string LED driver requires one unidirectional switch
for each LED string. So the cost of the proposed circuit is
lower than that of the multiple-string LED driver. Bidirectional
switches are somewhat expensive than unidirectional switches.
However, one expects that the cost difference between the
proposed circuit and the PFC buck converter would be
insignificant because the proposed circuit does not use any